Many high speed data transmission networks rely on optical links to communicate digital data. For each direction of such an optical link, the link includes an optical transmitter (such as a laser), an optical fiber, and an optical receiver (such as a photodiode). For proper optical coupling of the optical transmitter to the optical fiber, the optical transmitter is often included as part of a “transmit optical sub-assembly” or “TOSA”. For proper optical coupling of the optical receiver to the optical fiber, the optical receiver is often included as part of a “receive optical sub-assembly” or “ROSA”. The optical transmitter converts outgoing electrical data signals into outgoing optical data signals which are coupled into the optical fiber. The optical receiver receives optical signals from the optical fiber and converts incoming optical data signals into incoming electrical signals.
In normal operation, the optical signals are confined within the optical link, being substantially contained within the optical fiber, the transmit optical sub-assembly and the receive optical sub-assembly. Accordingly, the optical signals are not typically emitted into the environment. However, there are realistic scenarios in which the optical link can fail to the point where optical signals are leaked into the environment. For instance, the optical fiber might be severed, or may become unplugged at either end of the optical link. In that situation, if the leaked optical signal were to be received into the human eye, harm might result. Accordingly, various standards have been proliferated in order to guard against harm to the human eye when signals are propagated optically.
Typically, such safeguards take the form of keeping optical signals below a certain optical threshold for given time periods. The lower levels of optical power unfortunately tend to make faster optical power transmission rates much more difficult to achieve. Accordingly, there remains a need in the art to permit optical transmission at higher data rates while retaining safeguards protecting against harm to the human eye should optical leaking occur.